The invention relates to a battery clamp by means of which a battery can be connected, in particular a vehicular starter motor battery, as well as to a battery which is particularly suitable for being used in combination with such a battery clamp.
The problem during making contact with a battery contact is that for a reliable contacting there has to be maintained a defined contact force as precisely as possible. With the contact forces being too low, there will only be produced an insufficient metal-to-metal contact between battery contact and battery clamp. If, however, there are applied contact forces which are too high, this will result in a deformation and flowing of the battery contact material.
The most common battery clamp is comprised of a contact strap which is placed on the battery contact and subsequently is pulled tight by means of a screw bolt. It is a disadvantage with this type of battery clamp that the contact force which in fact is applied can be monitored only in an insufficient way. On the one hand, there is the danger that, by pulling tight of the screw bolt with a wrench, a much higher tightening moment and, thus, a much higher contact force is applied than would be actually required. On the other hand, there is the danger that, whenever the battery clamp is used with an already deformed battery contact, the contact strap is pulled to block by the screw bolt, so that a high tightening moment will be obtained for the screw bolt which, however, does not correspond with the lower contact force that will be achieved actually.
From prior art there are further known various battery clamps which employ spring elements that are intended to guarantee a constant contact force. These battery clamps, however, are of a comparably complicated construction.
Therefore it is the object of the invention to provide a battery clamp which is able to be manufactured in a simple and cost-effective manner and at the same time is fail-proof in terms of process, i.e. a battery clamp which can be assembled with high reliability both manually and in an automated way, without the danger of faulty assembly occurring. It is further the object of the invention to further develop the known vehicle batteries to the effect that they are able to be implemented with such a battery clamp.
According to the invention, a battery clamp is provided which comprises a contact ring that can be placed on a battery contact of a battery to be connected, a spring ring capable of pressing the contact ring against the battery contact, and a press-on housing capable of pressing the spring ring against the contact ring. This battery clamp is based on the basic idea to use as few components as possible, which are of a simple construction and are optimally adapted to the function which is to be fulfilled by them. The contact ring, to which a battery cable may be crimped, serves exclusively for contacting the battery contact. The contact force by means of which the contact ring can be elastically pressed against the battery contact is provided by the spring ring. The press-on housing has merely the task to press the spring ring onto the contact ring.
According to the preferred embodiment it is provided for that the contact ring is provided with several elastic contact tabs that together form a ring, the middle axis of which is coincident with the middle axis of the battery contact to be contacted. In this arrangement, it is preferably provided for that the contact tabs are curved, so that they touch the battery contact in a region which is spaced from their free end at which the spring ring engages. Furthermore, it is preferably provided for that the free ends of the contact tabs are bent, so that the ring defined by the contact tabs has a slope surface at which the spring ring engages. With this design of the contact tabs, the spring ring may be slipped on the slope surface of the ring that is formed by the contact tabs, so that the contact tabs are elastically prestressed. The elastic prestress of the contact tabs is possible, because their point of contact with the battery contact is spaced from that region at which the spring ring engages the contact tabs. The prestress of the spring tabs adds to the prestress through the spring ring, so that even with settling phenomena between the contact tabs and the battery contact, there will be maintained a sufficient contact force over a long period of time.
According to the preferred embodiment of the invention it is provided for that the contact ring is provided with several holding lugs by means of which it is latched in place on the press-on housing. It is further provided for that the press-on housing is provided with several detent tabs which cooperate with the holding lugs. In this way, the press-on housing and the contact ring are joined into a unit.
According to the preferred embodiment of the invention, there is provided a press-on lid to which the press-on housing is attached. The press-on lid fulfills a number of functions. It can be provided with a projection which is able to engage into a recess in a skirt of a battery to be connected. It is in this way that there is made use of a lever effect by means of which the force can be increased which is applied by the press-on lid via the press-on housing onto the spring ring. Further, there can be provided a locking tab on the press-on lid, which locking tab is able to engage a skirt of a battery to be connected. This allows to lock the entire battery clamp on the battery.
According to the preferred embodiment it is provided for that the press-on lid is provided with two elongated slots and the press-on housing is provided with two pins which engage in the elongated slots. In this arrangement, the pins preferably lie on a line which intersects the middle axis of the battery contact to be contacted. This ensures that there will not occur any tilting forces during pressing on of the press-on housing, as the spring ring is loaded symmetrically.
According to the preferred embodiment of the invention there is provided a blocking tab which in a blocking position extends as far as into the space that is occupied by the battery contact, the blocking tab preventing in the blocking position the spring ring from being slipped on the contact ring, and the blocking tab being able to be brought by the battery contact into a release position in which the spring ring can be slipped on the contact ring. Thus, the blocking tab increases the process safety to this effect that the spring ring can only be slipped on the contact tabs of the contact ring if the contact ring is placed on a battery contact. An unintentional xe2x80x9cclosingxe2x80x9d of the battery clamp prior to being correctly placed on a battery contact is prevented.
The above object is also solved by a battery that is wherein there are provided a battery contact and a skirt, the skirt surrounding the battery contact. On the one hand, the skirt serves as a mechanical protection for the battery contact. On the other hand, it opens new possibilities of fastening the battery clamp. The skirt may be provided with a recess, for example, which can be engaged by the projection of the press-on lid of the battery clamp. Furthermore, the skirt may be provided with a shoulder which can be engaged by the locking tab of the press-on lid of the battery clamp.
It is preferably made provision that the skirt is provided with a cut-out through which a connecting section of a contact ring extends, the contact ring being provided with a stop that cooperates with the skirt, so that a strain relief is produced. This makes sure that any forces that act on the connection cable, are not transferred to the battery contact and the battery clamp. Advantageous designs of the invention will be apparent from the sub-claims.